The imperial gallon is a unit for measuring a volume of liquid or the capacity of a container for storing liquid, not the mass of a liquid. Thus, a gallon of one liquid may have a different mass from a gallon of a different liquid.

An imperial gallon of liquid is defined as 4.54609 litres, and thus occupies a space equivalent to approximately 4,546 cubic centimetres (roughly a 16.5cm cube).

The U.S. liquid gallon and the U.S. dry gallon are different units defined by different means. The U.S. liquid gallon is defined as 231 cubic inches and equates to approximately 3.785 litres. One imperial gallon is equivalent to approximately 1.2 U.S. liquid gallons.

The U.S. dry gallon is a measurement historically applied to a volume of grain or other dry commodities. No longer commonly used, but most recently defined as 268.8025 cubic inches.

Whilst every effort has been made to ensure the accuracy of the metric calculators and charts given on this site, we cannot make a guarantee or be held responsible for any errors that have been made. If you spot an error on this site, we would be grateful if you could report it to us by using the contact link at the top of this page and we will endeavour to correct it as soon as possible.